js 拖动排序

DOCTYPE html>
html>
 head> 
  style>
.item img {
width:200px;
height:200px;
}

.item {
margin-bottom: 20px;
}

style> 
 head> 
 body> 
  div id="drag-wrap"> 
   div class="item" id="wrap1"> 
    img src="http://photos.tuchong.com/38538/f/6864556.jpg" id="img1" draggable="true" /> 
   div> 
   div class="item" id="wrap2"> 
    img src="http://photos.tuchong.com/349669/f/6695960.jpg" id="img2" draggable="true" /> 
   div> 
   div class="item" id="wrap3"> 
    img src="http://photos.tuchong.com/349669/f/6683901.jpg" id="img3" draggable="true" /> 
   div> 
   div class="item" id="wrap4"> 
    img src="http://photos.tuchong.com/349669/f/5121337.jpg" id="img4" draggable="true" /> 
   div> 
  div> 
  script>
const dragCon = document.getElementById(‘drag-wrap‘);
dragCon.addEventListener(‘dragstart‘, startDrag, false);
/**
* 这里一定要阻止dragover的默认行为，不然触发不了drop
*/
dragCon.addEventListener(‘dragover‘, function (e) {
e.preventDefault();
}, false);
dragCon.addEventListener(‘drop‘, exchangeElement, false);

function startDrag(e) {
console.log(e)
e.dataTransfer.setData(‘Text‘, e.target.id + ‘;‘ + e.target.parentElement.id);
}
function exchangeElement(e) {
e.preventDefault();
const el = e.target;
let PE, //要插入位置的父元素
CE; //需要交换的元素
if (el.tagName.toLowerCase() !== ‘div‘) {
PE = el.parentElement;
CE = el;
} else {
PE = el;
CE = el.querySelector(‘img‘);
}
/**
* 判断不在控制范围内
*/
if (!PE.classList.contains(‘item‘)) {
return;
}
const data = e.dataTransfer.getData(‘Text‘).split(‘;‘);
//交换元素
document.getElementById(data[1]).appendChild(CE);
PE.appendChild(document.getElementById(data[0]));
}
script>  
 body>
html>